In the past, in order to make cameras to be conveniently portable, the cameras grow popular ones adapted with a retractable lens barrel, wherein the interval between the lens units is shortened so that the lens barrel can be reduced in length.
Further, in the recent years, such lens barrels are structured in such a way that the interval between each optical element of the image capturing optical system is reduced in the optical axial direction, as well as some optical elements are shifted off axial to the other elements, so that the lens barrel is structured to be shorter.
Concerning the above lens barrel, the camera incorporating such a lens barrel is disclosed. That is, the lens units sandwiching a light-amount control member are shifted adjacent to a front group lens, while another lens unit is shifted into a position in a concave section of a member to support an image capturing element, in which the position where the latter lens unit is shifted is different from that of the former lens units (see Patent Document 1).
[Patent Document 1] Unexamined Japanese Patent Application Publication No. 2004-317943 (FIGS. 34-44).
In the lens barrel described in Patent Document 1, it is possible to shorten the length of the lens barrel, because the plural lens units are shifted when the lens barrel is retracted.
However, in case that plural lens units are shifted in different directions out of the optical axis, and returned onto the optical axis for image capturing, it is very difficult to accurately re-position the plural lens units on the optical axis, and still further, repetitive errors are generated so that an image capturing characteristics of each camera may differ. In particular, if the lens units, placed while sandwiching the light-amount control members, such as a shutter and an aperture diaphragm, are shifted and returned, the image capturing characteristics change abnormally, and thereby periphery image quality becomes uneven, which is a drawback.